Ok, I read your clarification, so I apologize, but I also thought it was just you from 8-5pm.
I think I've missed some posts, but if he is high needs, then he's got to get out of the house and possibly to some playgroups. High needs means that they need a ton of stimulation.
Also, on the not knowing how to play w/a toddler, I understand that. I often end up just watching my daughter, dumbfounded. You might read the book "Playful Parenting". It is full of stuff. I've also studied the way that my retired school teacher MIL plays with my daughter. Watching someone else has given me lots of ideas. Also, if you try one of classes, like a music class, it will give you ideas.
In addition, whenever possible I give my daugther (17 months), tasks, or have her do things herself. It helps combat their feelings of frustration that they are not in control and they look so proud afterwards. My daughter has to put her bib away after dinner and carry her spoons to the sink. Mind you, there is a ton of guiding involved. She also helps out with laundry and putting away groceries.
Also, have you tried babysmash.com? That might help with the laptop interest. My daughter loves the laptop as well. When we Skype with family members I use another program to lock the keyboard as well. My husband has a similar program on his phone.
Also, if you have a laptop, have you tried working at the park or outdoors somewhere? You mentioned cold weather, so I guess you can't do that right now, but maybe in a couple of months. That would mean he could play with other kids as well.
Working at home with my daughter is a dream, so I am very envious. Today, I'm home sick with daughter in daycare, blah.